A contaminant detector is capable of sending a signal or alert when a contaminant is detected within a housing of a utility meter, a meter transmission unit (MTU), or other associated equipment. Circuitry enclosed within the housing is capable of detecting utility usage, transmitting information between one or more utility meters and a utility provider, and/or otherwise monitoring or tracking utility usage. The contaminant detector includes a resistive voltage divider network having a resistance that varies when in contact with a contaminant such as a form of water or metal. The variable resistor has a serpentine structure comprising a plurality of detective fingers that are formed from conductive material and separated by a non-conductive substance.